One ant sinks in water, but a bunch of them? It turns out they can link together and become an unsinkable life raft. New research shows that when fire-ants are dropped in water, they quickly form a pancake-shaped floating mass, which traps air beneath them.

The results are incredibly buoyant (a process the researchers liken to weaving waterproof baskets). The trapped air also protects the bottom layer of ants from drowning, and as individual ants are removed, the others shift positions to balance out the mass.

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Rather than a beautiful instance of cooperation, it looks like this process may be a forced one, as those towards the edge of the ant mass are forcibly held in place by their neighbors.

The study was trialled on masses of ants numbering between 500 and 8,000. Each group successfully formed a raft. The behavior is an adaptation that's extremely useful in the ants' Brazilian rainforest habitat, due to frequent floods. Scientists compared the behavior of the ant masses to a fluid, with each ant acting as a molecule of the liquid.

Here's the upshot: If you can't drown them, I guess fire's the only answer.